Because sales tax is regressive — disproportionately affecting poorer residents — the decision to raise or lower the sales tax rate is often accompanied by intense debate. Still, last year, hundreds of cities and several states raised sales tax rates, although many others lowered rates as well.

Sales taxes are levied by both state and local governments. The rates, however, vary considerably between states. To determine the states with the highest and lowest sales tax, 24/7 Wall St. reviewed data aggregated by the Tax Foundation. The ranking is based on the sum of the statewide sales tax rate and the average of local sales tax rates.

A statewide sales tax is levied by 45 states, and local sales taxes are collected in 38 states. Delaware, Montana, New Hampshire, and Oregon levy no sales tax whatsoever at either level. California has the highest statewide sales tax rate at 7.25%. However, when considering the combined rate — which includes the average of local sales taxes — Louisiana’s sales tax rate of nearly 10% is highest of all states.

Sales taxes increase the cost of living in an area. However, states with high sales taxes are not necessarily the most expensive states to live in, and in fact are often some of the cheapest areas to live in the country. In both Arkansas and Alabama the combined sales tax exceeds 9%, each among the five highest of all states. Despite the high sales tax, Alabama has the third lowest cost of living among states, and Alabama is the second most affordable state in the country. Many of the states with little or no sales tax have among the higher costs of living.

While many states balance revenue between a number of taxes, including income, sales, and property taxes, a few states opt out of one or more major types of taxation entirely. In Oregon, where there is no sales tax, roughly 41% of state and local collections come from income tax, the highest share of tax revenue from income tax in any state. By contrast, in Washington, where there is no income tax, the combined sales tax rate is the fifth highest in the country, and sales tax accounts for nearly 45% of the state’s tax revenue.

The question of whether to levy income or sales tax is often deeply polarizing. Just over half of states earn more revenue from income than sales tax. Income tax allows for a higher share of revenue to come from affluent residents. A high sales tax disproportionately affects poor residents, as they pay a higher share of their income in sales taxes than wealthier residents.

To determine the states with the highest and lowest sales tax, 24/7 Wall St. reviewed sales tax rates from the Tax Foundation’s State and Local Sales Tax Rates in 2017 report. Combined sales tax figures include statewide sales tax as well as the average local sales tax for residents as of January 1, 2017. Regional price parity data is from the Bureau of Economic Analysis for 2014. Personal income per capita is also from the BEA for the third quarter of 2016.